Furnace construction



.vf-Nov, 13

y P. H. MCKENZIE FURNACE CONSTRUCTION Filed Aug. 9, 1920 2 Sheet-Sheet 1 Nov. 13 1923. y m7397311 P. H. -MCKENZIE FURNACE CONSTRUCTION FiledAug. 9, 1920 2 sheets-Sheet 2 Patented Nov. 135, 1923.

PETER H. IVIGKENZIE, OF CHICAGO, ILLINOIS.

E URNACE CONSTRUCTION.

Application filed August 9, 1920.

To @ZZ whom t may concern.'

Be it known that I, PETER Il. MCKnNZiE, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Furnace Construction, of which the following is a specification.

This invention relates to improvements in furnace construction and has for its object to provide a new and improved means for creating a natural or forced draft for a chain grate stoker. In the embodiment of my invention shown in the accompanying drawings, I provide a plurality of separately controlled air ducts just beneath the upper path of travel of the chain grate and closely adjacent thereto. I am thereby enabled to apply the draft properly through the entire bed of fuel and to regulate the same, if desired, at various sections of the fuel bed, in accordance with existing conditions. In present day construction, it is the practice to supply the air for combustion either by forced or natural draft to the entire 'body of fuel as a unit with the result that the fuel bed becomes burned out, or holes, as they are termed, are formed therein through which the air will rush seriously interfering withI the proper function of the furnace.

Other objects of my invention consist in the provision of means for the control of draft through the conduit members, and the provision of means to permit ready cleaning thereof. These and other objects will be more fully described and set forth in the following specilication and shown in the accompanying drawings, in which- Fig. 1 is a side elevation of a detail of an embodiment of my invention, a portion of the draft chamber thereof being broken away for clearness:

Fig. 2 is a vertical transverse section. along the line 2--2 of Fig. 1;

Fig. 3 is vertical longitudinal section of a detail taken along the line 3 3 of Fig. 2; and.

Fig. Il is a plan view of a portion of the mechanism showing a portion thereof as broken away for clearness.

Like numerals refer to like elements throughout the drawings in which- 10 indicates generally an endless chain grate stoker formed, for example, of the usual links 10a. carried upon the rods or shafts 11 (see Figs. 2 and 3), suitable draft Serial No. 402,479.

apertures or passages 10b being provided between adjacent links to permit access for the air for combustion to and through the fuel body. The chain grate mechanism is supported by and travels upon the rollers 13 spaced apart, as shown in Fig. 8 for example, it being well known to those skilled in the art that the under or returning portion of the chain grate is also suitably sup ported upon similar rollers 13 which engage those faces of the links which support the fuel during their travel in the upper orbit.

Located between spaced apart rollers 1?) are the draft boxes 15, shown as provided with the arched upper walls 15, perforated at 15b, these perforated walls being located just beneath the path of travel of the chain grate links so as not to be contacted thereby. At one end each of the boxes 15 is in communication with a draft chamber 16, being secured thereto by suitable clamping plates 1T and bolts and nuts 18, see Fig. 2 for example. the draft boxes being flanged at 15C to permit such clamping.-

The draft chamber 16 is tapered from the front of the furnace toward its closed end 16a, see Fig. 1 for example. At its other end 1Gb, this chamber 16 is secured to the air duct or elbow 16. provided with a butterfly valre or damper A, controlled by the rod 19 and arm 18a. This duct 16 is in communication with conduit 20, which in turn communicates with a centrifugal fan or other suitable air circulating means not shown. such fan being available to force air through duct 16 and therefrom to air chamber 16.

A sliding gate or valve 21 is provided for each of the draft boxes 15 at the juncture thereof with the draft chambers 1G. these doors sliding between flanges E21a and the side walls 16 of the draft chamber 16. see Fig. 9.. Suitable spacing strips 2i? servo to properly space the plates 21 from the eide wall 16, the bolts serving to also inail I these` members in proper relation. Each ot' the doors provided with an angle member 24. the outwardly extending flange 91"' thereof being engaged by the threaded end 25a of the operatingrod 25 which is secured thereto by nuts 26, or the like, see Figs. 2 and il for example. The innermost of the rods 25 is substantially straight throughout its length, the remaining rods being parallel therewith and having their inner ends bent inwardly adjacent their engagement with the respective gates or elves 21. The engageable ends CII h ofthe rods 25 projectoutwardly through the-elbow 17, seeiFig. l for example. It will be apparent that each ofthe gates 21 may be adjusted, as desired, to regulate the draft through the boxes l5. 'Ihe draft chamber 16, as stated, is tapered to compensate for the gradually decreasing volume of air flowing through the same.

At their opposite ends the boxes l5 are provided with doors similar to the valves or gates Q1 and similarly controlled byrods 3l topermit inspection or cleaning out of the boxes when desired. rIhedraft chamber isprovided with va removal cover'rplate 1GO, see Fig. 2, for the purpose of inspection and cleaning.

By the'mechanism described above. it is possible to regulate the draft, eitherforced or natural, as desired, at various points beneath the fuel bed and, should'the'iire become'thin and holes occur in any section of the bed, all of the draft air willnot rush therethrough but Vmerely a small portion thereof sothat the draft to the balance of the .fuel bed is substantially unimpaired. Also as will be obvious. should one section of the bed require more or less draft., it may be accommodated by a proper manipulation of the valves and yoperating rods.` A further advantage consists in the delivering of the air draft directly-beneath the fuel bed in such wise as to insure its passage through the bed without `the establishing of any short circuitl as in present day construction, thus eliminating the necessity for seals at the ash delivery end of the grate. Then forced draft is used, air under pressure is delivered to the boxes l5 by a fan or pump or other suitable means. At times, however, the'pressure may be discontinued and the air drawn through the line b v natural draft. i

It will be obvious that my invention is susceptible to numerous modifications and improvements and I do not wish to be restricted to the form shown except as defined in the appended claims.

l. In combination with a movable fuel supporting means, azplurallity of air ducts located transversely 'therebeneatln and Vspaced apart to permit of natural draft `supporting `means,a plurality of'air supply ducts located transversely therebeneatlnthe upper surfaces of said du'ctsbeing .perforated and located closely adjacent said supporting means, and said ductsbeing spaced to permit natural draft therebetween.

3. In combinationwith a movable 'fuel supporting means, a plurality of Lair ducts located transversely therebeneath and spaced'apart to permit of "natural draft therebetween,fthe upper surfaces of said ductsk being perforated. and located closely adjacent said supporting means, means to suppl.v air under pressure at said ducts, land meansto regulate or cut `ofl" saidpressure supply. the said upper surfaces of said ducts being arched to expose substantially the entire area of vfuel carried'by said Vsupporting means to the natural Adraftin the event said pressure supply is cut off.

el.. In combination n-'it-hamovable fuelsupporting` means, aplurality of air supply ducts locatedtransversely therebeneath, theV upper surfacesof said ducts being-perforated and located closely adjacent. said supporting means, and means to 'supply air under pressure to said chiots, said means comprising a duct extending longitudinally of said supporting means at one side offlthe latter and communicating with each of said first-named ducts, said longitudinally extending duct being'tapere'd and of largest cross-sectional area at its inta-lie end to compensate for the gradually decreasing volume o't' air flowing-throughthe same.

In testimony whereof, I 'have subscribed my name..

PETER I-I. MCKENZIE. 

